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E. D. KENDALL. PROCESS FOR PRODUCING COAL TAR DYES.

APPLICATION FiLED APR. 5. I818.

Patented Dec. 30,1919.

INVENTOR 5010M! D JwA/Zfv UNIT D STATES EDWARD D. KENDALL, or ELIZABETH, new JERSEY, nssrerron no esteem ns'razen,

.- me, A conronea'ion (in NEW YORK.

PROCESS rosireontrcme coenma Dans.

Specification 01' Letters Patent. Patented D962. 3% litl iith Application filed April 5, 1918. Serial No. 226,925.

To all whom it may concern:

Be it known that I, EDWARD D. KENDALL, a citizen of the United States, residing at Elizabeth, in the county of Union and State of Newfilerse have invented a new and useful Process or Producino of which invention the following is a specification.

This invention relates to processes of producing dyes from intro-substitution products of benzene and homologous hydrocarbons and their amido-derivatives and its object is to produce dyes by electrolysis in such method as to avoid the production of indulm blacks; in order that this shall be accomplished it is necessary to prepare an electrolyte containing an agent that shall act to control and liinit the oxidizing action at the positive electrode; after many experiments I have found such an agent in dimethyl ketone, that is acetone, which acts as a preventive of excessive oxidation thereby preventing the forming ofindulin blacks, limitingthe oxidizing action to color-production from the amide-body or bodies generated by reduction of the said nitro-body or bodies and favorably modifying the colors of the dyes produced.

Any suitable forms of electrolytic cells may be used v with or without contained porous cells and with electrodes of any suitable materials. I prefer to use electrodes of hard graphitic carbon. The simple form of electrolytic cell shown by the accom ian ing drawing will answer the purpose. n higures 1 and 2 of this drawing, a represents the carbon anode and Z) the carbon cathode; 0

represents the container of the electrolyte;

this container may be of any suitable mate rial, when small, of glass, when large, of

chemical stoneware. i

In carrying out my invention I dissolve,

Coal-Tar Dyes,

I put this electrolyte, so prepared, into an ea I electrolytic cell which should be kept cool by any available well-known means, as by placing it within a larger vessel containing cold water, with or without ice. This electrolytic cell may be covered to limit evapora ac tion and the'greater part of the acetone may be recovered finally by distillation.

An electric current of ten to fifteen volts may suffice for one electrolytic cell, the reouired potential varyingsomewhat with the dimensions of cells and, of course, increas ing with the number of cells arranged in series. 5

Reduction of the nitrohydrecarbons in, contact with the negative electrode gen "10 crates the corresponding amide-derivatives and these in contact with the positive electrode and under the influence of the acetone yield the dyes free from indulin blacks and also by chemical action of the acetone, with. favorably modified tints,

I claim:

The herein described process of producing dyes from nitrobenzene and homologues thereof by electrolyzing an electrolyte coir 8G sisting of one or more of the said nitro bodies, acetone, water and sulfuric acid.

EDWARD D. KENDALh.

It is hereby certified that Letters Patent No. 1,326,665, granted December 30, 1919, upon the application of Edward D. Kendall, of Elizabeth, New Jerse'y,for an improvement in Processes for Producing Coal-Tar Dyes, were erroneously issued toHeggin Estate, Inc., a oorporatiouof New York, as owner of said inventlon, whereos seirl Letters Patent should have been issued to the inventor, said Kendall, and Haggin Estate, Inc., jointly, said corporation being assignee of one-half interest only, as shown by the recorils of assignments in this office; and that the said Letters Patent should be read with this correction therein the the same may conform to the reeord of the case in the Patent l V Signed and sealed this 17th dy of Febuerj A. 11,1920. l

mm J H. COULSTON,

Acting amal am" gram,

101. zoo-61; 

